Physics

Rhyolite Definition Rhyolite is a usually light-colored, fine-grained extrusive igneous rock that is compositionally similar to granite. It often includes flow lines formed during the…

Volcanic Ash Definition Volcanic ash is a combination of fine particles made of rock, tiny strands of supercooled lava called volcanic glass, and minerals. It…

Silica Fume Definition Silica fume is a co-product from the production of silicon or ferrosilicon metal. Silica fume is a mineral admixture, a very fine…

Moissanite Definition Moissanite is a rare gem that has almost all of the qualities of a diamond. It was first discovered in 1893, with the…

Silicon Carbide Definition Silicon carbide (SiC) is an extremely hard bluish-black insoluble crystalline substance produced by heating carbon with sand at a high temperature and…

Germanium Definition Germanium is a brittle, crystalline, grayish-white metalloid element that is found in coal, in zinc ores, and in several minerals. Its atomic number…

Silicon Definition Silicon is a metalloid element that occurs in both gray crystalline and brown noncrystalline forms. It is the second most abundant element in…

About Brass Definition Brass is a yellowish alloy of copper and zinc, usually 67 percent copper and 33 percent zinc. It sometimes includes small amounts…

Tarnish Definition Tarnish is a substance which forms on the surface of some metals and which stains them or causes them to lose their brightness.…

Thorium Definition Thorium is a silvery-white, radioactive metallic element of the actinide series. The only naturally occurring isotope of thorium, Th 232, is also its…

Titanite Definition Titanite is a very rare calcium titanium silicate that is an important ore of titanium. It is also called Sphene. Its crystals are…

Datolite Definition Datolite is a colourless mineral consisting of a hydrated silicate of calcium and boron in monoclinic crystalline form, occurring in cavities in igneous…